Due to the light-weight and handleability, the excellent stability for preservation of the content media, and the inexpensive cost, synthetic resin bottles, representatives of which are oriented polypolypropylene (OPP) bottles and polyethylene terephthalate (PET) bottles, are used in various applications, such as beverages, foods, cosmetics, and so forth.
Such a synthetic resin container is known to include the trunk portion provided with reduced pressure absorbing panels to cope with so-called hot filling, in which the contents, such as a beverage, including a juice beverage and tea, and a seasoning, including soy sauce, vinegar, and dressing, are filled at a high temperature heated state. After the contents are hot-filled, the mouth portion is closed with a cap. Then, as the contents are cooled, the inside of the container is placed under reduced pressure, possibly causing the trunk portion to be deformed significantly. To address the above problem, the trunk portion is provided with the reduced pressure absorbing panels, which may be deformed to absorb the reduced pressure inside the container, thereby preventing the entire trunk portion to be deformed significantly.
For example, Patent Literature 1 describes a synthetic resin container including a trunk portion provided with reduced pressure absorbing panels, which extend obliquely in the vertical direction. Thus, the described synthetic resin container prevents deterioration in rigidity otherwise caused by a reduction in thickness of the container. Furthermore, with the reduced pressure absorbing panels that may be deformed to absorb the reduced pressure inside the container, the described synthetic resin container also maintains its appearance shape even when being hot-filled with the contents.